Saturday, May 7, 2016

How much for the sustainable energy transition? A "back of the envelope" calculation



Image source. "Back of the Envelope" calculations are a tradition in science and often turn out to be able to provide plenty of useful information, at the same time avoiding the common pitfall of complex models, that of being able to fit anything provided that one has enough adjustable parameters.


The world's economy can be seen as a giant heat engine. It consumes energy, mainly in the form of fossil fuels, and uses it to produce services and goods. No matter how fine-tuned and efficient the engine is, it still needs energy to run. So, if we want to do the big switch that we call the "energy transition" from fossil fuels to renewables, we can't rely just on efficiency and on energy saving. We need to feed the big beast with something it can run on, energy produced by renewable sources such as photovoltaics (PV) and wind in the form of electric power.

Here are a few notes on the kind of effort we need in order to move to a completely renewable energy infrastructure before it is too late to avoid the double threat of climate disruption and resource depletion. It is a tall order: we need to do it, basically, in some 50 years from now, possibly less, otherwise it will be too late to avoid a climate disaster. So, let's try a "back of the envelope" calculation that should provide an order of magnitude estimate. For a complete treatment, see this article by Sgouridis et al.

Let's start: first of all, the average power generation worldwide is estimated as around 18 TW in terms of primary energy. Of these, about 81% is the fraction generated by fossil fuels, that is 14.5 TW. This can be taken as the power that we need to replace using renewable sources, assuming to leave everything else as it is.

We need, however, also to take into account that these 14.5 TW are the result of primary energy generation, that is the heat generated by the combustion of these fuels. A lot of this heat is waste heat, whereas renewables (excluding biofuels) directly generate electric power.  If we take into account this factor, we could divide the total by a factor of ca. 3. So, we may say that we might be able to keep the engine running with 5 TW of average renewable power. This may be optimistic because a lot of heat generated by fossil fuels is used for indoor heating, but it is based on the idea that civilization needs electricity more than anything else in order to survive. In terms of indoor heating, civilization survives even if we turn down the thermostat, wear a multi-layer of wool, and light up a small wood fire.

Renewable installations are normally described in terms of "capacity", measured in "peak-Watt" (Wp), that is the power that the plant can generate in optimal conditions. That depends on the technologies used. Starting from the NREL data, a reasonable average capacity factor a mix of renewables can be taken as about 20%. So, 5 TW of average power need 25 TWp of installed capacity. We need to take into account many other factors, such as intermittency, which may require storage and/or some spare power, but also better efficiency, demand management, and storage. On the whole, we may say that these requirements cancel each other. So, 25 TWp can be seen as a bare minimum for survival, but still a reasonable order of magnitude estimate. Then, what do we have? The present installed renewable capacity is ca. 1.8 TWp; around 7%. Clearly, we need to grow, and to grow a lot.

Let's see how we have been doing so far. (The values in the figure below appear to exclude large hydropower plants, which anyway have a limited growth potential).



Image source

As you can see, we have been increasing the installed power every year. According to Bloomberg, the installed capacity reached about 134 GWp in 2015. If this value is compared with the IRENA data, above, we see that the growth of installations is slowing down. Still, 134 GWp/year is not bad. The renewable energy industry is alive and doing well, worldwide.

Now, let's go to the core of the matter: what do we need to do in order to attain the transition, and to attain it fast enough? (*)

Clearly, 130 GWp/year, is not enough. At this rate, we would need two centuries to arrive at 25 TWp. Actually, we would never get there: assuming an average lifespan of the plants of 30 years, we would reach only about 4 TWp and all the new installations would be used to replace the old plants as they wear out. But we could get to 25 TWp in 30 years if we could reach and maintain an installation rate of 800 GWp per year, about 6 times larger than what we are doing today. (note that this doesn't take into account the need of replacing old plants but, if we assume an average lifetime of 30 years, the calculation remains approximately valid from now to 2050.)

We may not need to reach 100% renewable power by 2050; 80% or even less may be enough. In such case, we could make it with something like 500 GWp/year; still a much larger rate than what we are doing today. And if we manage to arrive to  - say - even just 50% renewable power by 2050, then we will have created a renewable juggernaut that will lead to 100% in a relatively short time. On the other hand, as I said before, 25 TWp may be optimistic and we may well need more than that. On the whole, I'd say that 1TWp/year is as good as it can be as an order of magnitude estimate of the energy needed for the survival of civilization as we know it. Approximately a factor of 8 higher than what we have been doing so far.

This back of the envelope calculations arrives at results compatible to those of the more detailed calculations by  Sgouridis et al. That study makes more stringent and detailed assumptions, such as the need of increasing the supply of energy for a growing human population, a lower capacity factor, the need of a gradual build-up of the production facilities, the need of oversized capacity to account for intermittency, the energy yield of the plants (*) and more. In the end, it arrives at the conclusion that we need to install at least 5 TWp per year for a successful transition (and, by the way, that, if we do so, we can avoid crossing the 2 degrees C warming threshold). That's certainly more realistic than the present calculation, but let's stay with this scribbled envelope as a minimalistic approach. Let's say that, just in order for civilization to survive, we need to install 1 TWp per year  for the next 30 years, how much would that cost?

Let's see how much we have been spending so far, again from Bloomberg:


Image from Bloomberg Global clean energy investment 2004-15, $bn

As you can see, investments in renewable energy were rapidly increasing up to 2011, then they plateaued with the value for 2015 only marginally higher than it was in 2011. However, if we compare with the previous figure, we see that we have been getting more Watt for the buck. In part, it is because of previously made investments, in part because of the improvements in renewable technologies that have reduced the cost per kWp. But note that technological improvements tend to show diminishing returns. The cost of renewable energy in terms of watt/dollar has gone down so fast and so much that from now on it may be difficult to attain the same kind of radical improvements, barring the development of some new, miracle technology. For instance, at present solar cells represent only about 30% of the total cost of a PV plant. Even if we were able to halve that cost once more, that would result in just a 15% lower cost of installations. Take also into account that technological improvement may be offset by the increasing costs of the mineral resources needed for the plants.

We said that we need to increase the installation rate of about a factor of 8 in energy terms. Assuming that the cost of renewable energy won't radically change in the future, monetary investments should of about the same factor. It means that we need to go from the present value of about 300 billion dollars per year to some 2 trillion dollars/year. This is a lot of money, but not an unthinkable: amount. If we sum up what we are investing for fossils (about $1 trillion/year), for renewables ($300 billions/year) and nuclear (perhaps around $200 billions/year) we see that we are not far from there, as we can see in the image below. The total amount yearly invested in the world for energy supply is about 2% of the Gross World Product, today totaling about US$78 trillion.



And there we are. The final result of this exercise is, I think, to frame the transition as a "mind-sized" model (to use a term coined by Seymour Papert). Basically, it turns out that, barring technological miracles, a smooth transition from fossils to renewables is probably impossible; simply because the current way of seeing humankind's problems makes it impossible even to conceive such a massive shift of investments as it would be needed (noting also that investments in renewables have not been significantly increasing from 2011 - that's bad).

This calculation also tells us that it is not unthinkable to advance in the right direction and attain a transition that would allow us to maintain at least some of the features of the present civilization. That is, if we are willing to invest in renewable energy, our destiny is not necessarily that of going back to middle ages or to hunting and gathering (or even to extinction, as it seems to be a fashionable future in certain circles). The transition will be rough, it will be difficult, but it will not necessarily be the Apocalypse that many predict.

In any case, some kind of transition is unavoidable; fossil fuels just have no future. But civilization may still have a future: all the investments in renewable energy we can manage to make today for the transition will make the difference for the future. This is a choice that we can still make.



(*) Note: In this simplified calculation, I haven't specified where the energy needed for building the new infrastructure will come from and I haven't used the concept of EROEI (energy return on energy invested). It is taken into account in detail in the calculations by Sgouridis et al in terms of the concept of the "Sower's Strategy", that is assuming that fossil fuels provide the necessary energy during the initial stages of the transition, then they are gradually replaced by renewable energy. 





51 comments:

  1. Ugo the math on primary energy generation seems flawed, isn't that 14.5 output not input? Meaning you dont get to divide renewable needs by 3, and we need 14.5 TW renewable output to match fossil fuel generated oitput. Suddenly thats 6% of gdp per year investment and a less rosy picture.

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    1. This is a controversial and often obscure point. The Wikipedia definition of "primary energy" is "an energy form found in nature that has not been subjected to any conversion or transformation process. It is energy contained in raw fuels. So, if I burn a barrel of oil I get a certain amount of Joules of energy in the form of heat. But, normally, I don't need heat; I need traction or electric power; so I must use a thermal engine to transform heat into useful energy. Hence the loss of about 70%. PV and wind do not have this need

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    2. Hello, Hugo. It's not an obscure point. You are right in your post. Primary energy refers to gross energy, not to net energy. According the BP Statistical report the primary energy was in 2014 412 Tmoe/second or 17.2 TW. Regarding the global oil production in 2014 it was approximately 150 Tm/second. So, it's evident that your primary energy data refers to gross energy. Regards.

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    3. Ok I see its complicated... But it seems that the final conversion still isn't going to be a factor of three. A lot of those fossil fuels in that total are burned directly in engines at efficiencies you wont really improve by using renewable electricity - it also has to go through a few conversion/transmission processes to be used that way. I'm making this point as it has a large impact on your calculations. See https://en.wikipedia.org/wiki/World_energy_consumption

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  2. Yes it is a nice first "back of the envelope calculation" that also makes a number of assumptions which I think should be made more explicit and tested. In the more detailed calculations to follow it would be equally "nice" to see a real plan and a believable analysis of the political economy of change (and of the politics of change) for the transition at least at global and national levels. (Regional and local levels can come later) Once that is sketched out the "realism" of the exercise can more easily be discussed and the tacit good guys and the bad guys also can be idetified.

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  3. How much embedded energy is there in each PV Panel in order to manufacture it, and where is that calculated on the back of the envelope? Also, what is the lifespan of each PV Panel, and how often must it be replaced? Also, where is the calculation for all the batteries needed to store the energy from these PV panels, and how is this energy used to power a transportation system?

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    1. Details about embedded energy are in the paper by Sgouridis, Bardi and Csala linked in the text. Lifespan is around 30 years. About batteries and transportation, sorry, right now I have to leave... my electric scooter is parked just in front of my house....

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    2. I have an electric scooter too Ugo. It does 15mph and has a range of about 12 miles.

      A scooter is not a truck hauling 20 tons though or a train hauling 1000s of tons. You could run a third rail for the trains and dispense with the batteries, but then you have power loss along the rail and intermitancy problems with no SUN☼ at night and many windless days. Nor is a scooter heavy equipment used to mine up the materials from which solar cells are made.

      Where also on the back of the envelope is the calculation for the energy required to upgrade the electrical grid to handle the daily load of millions of vehicles currently running on FFs which now would require electrical energy once you do the fleet substitution for all EVs? Where is the money going to come from to upgrade said electrical grid?

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    3. Who sold you that kludge? My electric scooter makes more than 100 km and reaches 60 km/h. And, if you need, I know people who can rent you a heavy electric truck

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    4. Mine cost $500, how much did yours cost? Also, can you fold it up and carry it with you on a train or bus and drive it inside Food Warehouses?

      I'm sure there are electric trucks with massive battery banks, but I don't know of a single truckstop in the entire FSoA I could charge it up in any reasonable amount of time. I drove trucks over the road for 7 years, and at 500 miles/day average, you need a LOT of power, you refill on the diesel every day. So every truckstop now needs to be wired with high throughput power which takes some mighty thick wiring to pull off, and even so you are talking a couple of hours at least to jack enough charge into the battery for another 500 mile segment.

      You still haven't covered the back of the envelope calculation for the embedded energy required to upgrade the grid to handle this throughput, and you still have not dealt with the intermittancy problem for nighttime, cloudy and overcast days and windless days.

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    5. I see..... evidently, you bought it at Toys R Us. About the other questions, you seem to be too lazy to click on the link I provided in the post. Here it is again
      http://arxiv.org/abs/1503.06832

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    6. No, I actually had to have the damn thing shipped directly from China to a friend in the lower 48 because they wouldn't ship to Alaska, then he had to drop it on a trailer of another friend who was having his trailer barged up here because they wouldn't fly the thing air freight. It's no toy, it's quite a sturdy little thing actually.

      I'll go dick on the link and get back to you. :P

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    7. OK, Read it, or Reddit. I'll drop that link on my Reddit Channel. lol.

      I did not find in that paper any estimates for the cost of rewiring the electrical grid of the FSoA to power up a new fleet of Battery Powered Trucks and Heavy Equipment for mining necessary to get this system off the ground. Nor could I find a cost estimate for all the batteries needed for the new system. Please provide an estimate of the expense in building this infrastructure and it's ROI so I can submit it for an IPO for Goldman Sachs to underwrite, and we will both be richer than God.

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    8. h/t to lovely_lady on r/collapse for this link on why converting to electrics for trucks is unlikely.

      http://energyskeptic.com/2015/all-electric-trucks-not-going-to-happen/

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    9. Not to mention the leaching of toxic chemical from solar Pv panels into landfills for generations to come.

      SOLAR DEVICES INDUSTRIAL INFRASTRUCTURE
      http://sunweber.blogspot.com.au/2015/04/solar-devices-industrial-infrastructure.html

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    10. Alas, RE, you are old enough that you should know that lovely ladies shouldn't be trusted too much. As for heavy electric trucks, they are already here: https://en.wikipedia.org/wiki/Trolleytruck

      As old Jevons said, if you have coal (meaning "energy") you can do anything. If you don't have coal, you are back to the laborious poverty of old times

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    11. I have two scooters. The "old" one is limted to 30 mph by Italian law, and has a 50-60 km range. The new one reaches 65 mph and has a 100 km range. You get lots of these things today. On city usage, the equivalent mileage is ~100km/litre (one litre of oil equivalent burned in a power plant, including all generation ad transportation losses).

      For 500$ you get an e-bike. And try to carry and fold an endothermic scooter. Your is not a scooter, is something really different, for a different (and legitimate) use.

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  4. As far as I know, the energy statistics are usually based on the assumption that "traditional" energy conversion systems are in place. So for example in many energy balances, conversion from thermal energy units such as TOE to electrical energy units (kWh) are usually performed considering the average efficiency of the national generation system: although the heat generated by burning 1 TOE of fuel is equal to 11,630 kWh, the actual electrical energy produced by the Italian average generation plant is 5,384 kWh. This makes it tricky to use the data of today's energy production statistics to evaluate future energy systems based on totally different conversion technologies. I am not sure, for example, that 14.5 TW should be converted to final use in the form of electricity. I guess a large part of this amount is used directly as heat, for example to heat residential buildings, and to perform a large variety of industrial processes. If this is this case, we are not entitled to simply divide this value by 3. A better approach would be to start from the final energy need, and then work out what would be the required energy generation at the beginning of the conversion chain, assuming different conversion technologies for different scenarios. Another warning: when I started to consider these matters, not so long ago, I used to consider 15 TW as the global amount of energy consumption rate. Now, just 4 years later, we're up to 18 TW. Are we sure that in 50 years time we will still use energy at a rate of 18 TW?  

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    1. Correct. Maybe a factor of 3 is optimistic. About the 18 TW, again, we are playing with orders of magnitude. If we want a smooth transition, then we have not only to consider that value, but also to increase it to take into account the rising population and the need to provide energy to poor countries. If we just say we clench our teeth and fight for every kWh, then 15 TW may be even too much. It depends, as always....

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    2. And I also explained better in the text the reasoning that led me to the "factor of three"

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    3. What I meant is that, if we assume that energy usage will grow in the future as it did in the past (more than 2% per year), 15 TW or 18 TW will be just nothing in 50 years time. We will need more than 40 TW. All these calculations assume that energy usage, which is linked to the global amount of activities performed by human society, will for some reason remain constant. But that's exactly the idea of steady-state economy, which, IMHO, is impossible to even conceive in the general framework of today's mainstream economics. Energy efficiency, although possible, won't change the big picture. First, because there is a limit to the theoretical efficiency achievable, and we will bump into the financial limits much before hitting the physical limits. Second, because for many relevant technologies the theoretical limits are just 50% away (it would take only 35 years to use this margin up, at 2% growth rate). Third, because efficiency is not at all a new idea. The whole history of the industrial revolution is a history of unrelenting growth in efficiency. Nevertheless, the global energy usage has kept growing and growing. In many cases, this growth was exactly due to the spectacular improvements in terms of efficiency of basic technologies and processes. It is called the "Jevons paradox" or "rebound effect".

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    4. It depends of the use. Solar thermal could be more efficiente than PV in heat or cogeneration.
      And it depends on the use, sometimes 1:3 is correct, sometimes 1:1 or even worse (synthetic fuels, for example) is too. I assume that we will convert 1:3 first so we will take more time to reach bigger renewable power values.
      The impact will not be the same in different sectors anyway.

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  5. If we could make some kind of transition to renewables, would this let us significantly avoid or delay the other limits of growth? I am thinking other aspects of the world system algorithm (the real one, not model) still bite us in the you know where? Of course, your post was just about one issue, and not about the total system, but thought I would ask the questions to you as I am reminded often lately (and by many of your past posts) that addressing one issue may not be “the” solution.

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    1. For example, it's not immediately obvious how transitioning to renewables would limit population growth, which tends to deplete arable land and potable water.

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    2. This is a good question. My idea is that renewable energy could lead us to something like a zero-growth society similar to the one that existed in Japan during the Edo period. That model cannot be exported to become worldwide at the technological level of the Edo civilization; it needs communication and transportation technologies that the Japanese of that time didn't have. But with electricity, we could maintain long range communication and weave together the world's communities without seeing monster armies running through them all the time. Maybe.

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  6. Just a back of envelope thought.

    ‘Civilisation’ is leverage from energy. Never mind the apparently small-sounding fraction of GDP it costs now to provide the energy that drives global industrial economies (aka in this context “civilisation”). If it were to cost (energy, materials, time and etc.) double the amount of global industrial organisation to provide the electrical energy needed to cover future industrial output and its 'civilisation' (a 'package deal') at the rate provided just now, then, I suggest, we would see half the current global economy as a result.

    If I got this thought at least half correct I think it is because I read something like it written by Nate Hagens.

    best
    Phil

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    1. I think Nate is perfectly correct here. Civilization is a metabolic beast. The more food (energy) you feed into it, the more it grows. And it also becomes nasty and obnoxious, but it can be tamed.

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  7. First, a lot of energy is used for heating, at least in the higher latitudes. It is not in your calculation. - it can be slashed to a fraction of itself by decent insulation (zero energy houses), but not without a cost. Same holds for cooling: just using reasonable building techniques, good insulation, small windows, high thermal mass does a lot.
    Second, given the will to do it, it is definitely feasable to ramp up renewables installation. The gross world product is around 100 Trillion USD. World defense spending (totally wasted and even harmful use of creativity) is about 1.5 Trillion - that shows again, how important peace is for every aspect of life. Only the will is the crucial point.

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    1. Yes, it would be enough to funnel all the money wasted in military expenses into renewable energy. Just a small problem: they have all the guns

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  8. What no one here has so far mentioned is these "renewables" are also dependent upon a high energy, advanced manufacturing civilization AND some of their components are made from OIL.
    If it must have NON RENEWABLE resources to exist, it's NOT "renewable"!

    OIL, COAL & NATURAL GAS are used to provide the energy that powers the mining machines, the huge trucks that haul the raw material to the factory where it's processing into the metals, then into components, it's manufactured into solar panels, then finally, it's hauled across the pacific by huge ships burning dirty bunker oil.
    Clean? look at how dangerous it is to breath in China where most are made.
    If you think you can replace all that embedded energy with solar panels, I got this neat bridge in Brooklyn to sell you.
    Another problem is that NONE of those so called "renewables" produce ANY of the essential raw material we now get from fossil resources & non of the fertilizers we produce now from natural gas.
    Solar panels & wind turbines not only cannot produce reliable, steady electricity on demand, it cannot grow our food, produce synthetic fibers, paint, medicine, plastics etc or the portable, concentrated energy we need to power our transportation system.
    Solar cells, wind turbines & batteries are just not up to even beginning to replace fossil resources, we are in a heap of trouble.

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    1. And yet, sometimes one should realize that repeating the same old canards over and over, doesn't make them true........

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    2. "Solar panels & wind turbines cannot grow our food, produce synthetic fibers, paint, medicine, plastics etc"

      A very good reason for NOT burning oil. Keep it for these things, we don't have much of the stuff.

      For the rest, I travel mostly on electric transportation systems. I get reliable electricity from renewable energies.

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    3. I agree we're in trouble. But remember the quotation from Scott Fitzgerald:

      "the test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function."

      I think the point is that truly smart people are able understand that situation is hopeless, but still be willing and able to imagine that it can be improved or even saved.

      I don't thnik I'm being naive when I say that we have no choice but to try to make things better, and not give in to dispair!

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  9. An excellent thought-provoking essay. It provokes the kind thinking needed: Just where do we need to go? How do we get there? Is there a there there? In such thinking, it is too easy to get sidetracked.

    1. Like letting precision sidetrack accuracy. I applaud your attempt. By the way, Prof Tom Murphy kinda has a blog, “Do the Math” (dormant at present, but the old essays are as good as when they were published):
    physics.ucsd.edu/do-the-math

    2. Like insisting that trend be destiny. If you wish to sail from Chicago to Mackinac Island and the wind is dead north, you must tack. The eastern and western shores of Lake Michigan (a mostly north-south body of water) provide unavoidable limits to how far you can go on any tack. Besides, in these parts, assuming any wind pattern would hold long enough for the trip is preposterous. By the way, I did that little voyage on a 48' schooner back in 1957. (I was younger then.)

    3. False pessimism is as misleading as false optimism. Eeyore must not be married off to Pollyana.

    4. Most importantly, concepts like acceptable and unacceptable, like true and false, are unavoidably squishy. Wishfully we think of hard facts and want to take reality for granite… but the world is made of jello.

    Meanwhile, I do hope to read the Sgouridis et al paper.

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  10. How would you upgrade the first 25TWp after 2030?
    Electric concrete? Electric Lithium/Neodyme?
    Electric boat to replace offshore farms?

    Do you know how much fossil fuels are embedded in a PV system (not as energy content, but as primary inputs)?

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    1. Probably we could. I mean, you could use electricity based furnaces to make all this materials, but I'm confident that we will found better ways. Perhaps other materials and other ways to install solar energy are better, but even for these materials, a combination of preheating using solar concentration and later using electricity could bring better results that using only electricity.

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    2. Energy content and primary input are basically the same thing. Unless you mean if there is plastic somewhere in the system, and the answer is that there is very little; only for the insulation of the wiring.

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    3. Of course materials require a lot of treatments mostly based on fossil fuels processes. I'm not sure that PV panels require only small amounts of plastics. They are everywhere!

      By the way, why focusing on PV? It's quite known now that its EROI is very weak (perhaps less than 1). It would be more efficient to bet on wind, which has a much better EROI...

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  11. Where are the calculations for energy expenditure on the huge effort it would take to continue with fossil fuels? You still have to explore for more fuel, drill and ship it all going forward. Many current coal plants are past their use-by date and need to be replaced now anyway. Where are the calculations to replace all these old fossil plants and maintain them? Also the costs of externalities like the huge fire in Canada and the health costs of breathing particulates.

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  12. 1. The IRENA graph does appear to include large hydropower. Removing that from the discussion/equation and there is a much faster upwards curve in terms of growth in clean-energy additions/year.

    2. That the solar panel is ever less of installation cost is a key pointer toward the need to drive down soft costs -- from permitting to business development to finance. Last time I looked, German distributed (rooftop) solar was roughly 1/2 the price, per kw, installed than US projects. Cleaning up paper work, having increased scale, etc and the soft costs can go down quite a bit. And, 'tech' paths forward can drive this as well -- when BiPV (building integrated pv) is in the range of 'same cost' as non PV options, how much will the 'soft cost' of PV actually be (since its net incremental cost, compared to traditional slate roof (for example), might approach 0).

    2. Re hydro, there is decent room (though not 10s of terrawatts of capacity) for growth. For example, there are numerous US Army Corps of Engineer dams in the United States don't have energy-generation capacity that could. New large-scale hydro is not 'the' or even 'core' to eliminating fossil fuels but, on the other hand, doesn't merit rejecting out of hand.

    3. If we look across economy -- all uses (transportation, industrial, heating, etc ...) -- seems that the 'electricity efficiency' is roughly 1/3rd. (See this discussion: https://climatecrocks.com/2016/05/09/new-video-mark-jacobson-on-a-renewable-world/) E.g., rather than divide by 1/3rd, perhaps multiply by 0.7. And, then add in the additional generation required to address what are currently non-electricity demands. End up with capacity requirement in ballpark of today's ... ('ballpark' in sense of back of the envelope estimation).

    4. Going back to hydro -- a dam is often 100+ year operating life. Upgrades required, but long lived.

    5. "Assuming that the cost of renewable energy won't radically change in the future ..." is an incredibly pessimistic assumption. A few years ago, large-scale solar was in range of 20 cents/kWh contracted price. Latest bidding has it under 3 cent/kWh. There are reasonable discussions of how this is likely to in range/below 2 cents by 2020 timeframe. Wind is not as extreme but we're still seeing meaningful reductions in price for technological and business approach reasons. Not clear with wind, solar, ocean energy, etc that we are anywhere close to seeing the end of cost reductions.

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    1. The question of the possible improvement of solar technologies in the coming decades would require a detailed discussion. In short, however, I believe that we have a technology that's already mature and for which we can expect only marginal improvements, mainly as the result of scale factors.

      This is due to the basic characteristics of solar cells. We are facing some basic constraints: if we consider a VERY large expansion of solar, then we can't afford exotic and rare materials, such as CdTe or GaAs. We are stuck to silicon, which is a common material in the earth's crust. Silicon has a maximum theoretical efficiency of 30% as a solar cell material. We are already over 20% for commercial cells; we can inch up a little more, but these are marginal improvements. The same is true for the manufacturing, which is by now standardized.

      The only other possibility for large scale PV power is organic solar cells, they have been around for many decades but their efficiency remains much lower than that of silicon, and they degrade rapidly. Then, of course, you may think of multi-junction cells embedded in solar concentrators, that would solve the problem of lack of sufficient mineral resources. But if the idea is to lower costs, you are marching in the opposite direction.

      That doesn't mean that cell prices won't go down in the future. Just that they will follow the typical cost curve of most devices: they go down fast at the beginning, then they stabilize. And the point is that we don't have many decades to make the switch. We have to do it with what we have.

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  13. More techno utopian babble. Only drastic population reduction can save our biosphere.

    "despite a string of optimistic choices resulting in low values of energy investments, the ERoEI is significantly below 1. In other words, an electrical supply system based on today's PV technologies cannot be termed an energy source, but rather a non-sustainable energy sink or a non-sustainable NET ENERGY LOSS."
    https://collapseofindustrialcivilization.files.wordpress.com/2016/05/ferroni-y-hopkirk-2016-energy-return-on-energy-invested-eroei-for-photo.pdf

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    1. There is something called "cherry picking", you know, Harquebus?

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    2. I agree that without a drastic population reduction we will face dire times. But
      - I don't see many ways to force a population decrease, beyond a massive famine or other unpleasant ways. But I agree, we must do whathever we can to encourage a (voluntary) population reduction
      - the degree of difficulties we will face depends a lot on energy availability.

      Regarding the Ferroni&al paper. They make lots of PESSIMISTIC and unrealistic choices. Then they make just one or two optimistic ones and end up with that statement, that is blatantly false. Just to cite one, they consider 700 hours/year equivalent production, the real figure in Italy is twice that.

      Consider that now the equivalent price for FV is roughly twice the commercial base price for conventional electricity. If, as Ferrony says, the EROEI is 0.8, the cost of a FV plant should be 60% energy. Raw materials, industrial infrasctructure, labour, transportation, installation, know-how, electronics (beyond electronics gray energy) should be just 40% of the total cost.

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    3. Hi Ugo.

      Me or the authors of the report? I have others.

      A lot of cherries picked by renewable energy advocates as well. Usually by vested interests or economists who, do not factor energy nor the environment in their fundamentally and fatally flawed equations.

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    4. Hi Gianni.
      I have read the report and have come to a different conclusion. The report draws its data from Germany, that's north of Italy, where figures are more complete. A search did not find the figure 700.
      The environment is another factor that also must be considered. Toxic byproducts, 4 tonnes for every tonne of Pv panels, is dumped into the Chinese environment. That is why costs have come down.

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    5. And, of course, the last resort of the incompetent is to accuse those who don't agree with him/her of vested interests. Harquebus, you are banned from this blog.

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  14. I recommend this reading for growth in PV and saviongs of CO2:
    http://www.lowtechmagazine.com/2015/04/how-sustainable-is-pv-solar-power.html
    Another problem is the gird, we need a global grid or at least some sortof continental grid to average outintermittency. You did not mention any costs in the grid upgrade and that also is a HUGE installation worldwide...

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  15. I recommend this paper of mine. Just appeared on "BERQ"

    http://link.springer.com/article/10.1007/s41247-016-0002-z

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  16. sir: the fact that you are doing "back of the envelope" calculations relative to the costs of switching to renewable energy is itself very telling. if anyone was serious about such an endeavor these calculations would have been done far more rigorously long ago. the sad truth is that short term thinking precludes such long range planning and the entities with the trillions to invest are fixated on y-o-y results, share price and current yield and could hardly care less about events 50 years hence.

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  17. I agree that we need to transition 1TWp/year 'carbon free energy' in order to reduce emissions at a rate that will mitigate environmental risk. This constitutes an environmental imperative.

    As 'carbon free energy' prices drop to one tenth of the cost of coal, this transition, 1TWp/year, takes on an economic imperative, creating a race to convert. Converting creates jobs and those conversion costs are quickly recovered, then those monies become yearly savings. The faster a nation converts the sooner those energy savings benefit and stimulate the economy.

    This strong economic imperative to convert creates a whole different 'carbon free by 2050' scenario than the one presented here. Consider (search) 'Emergent LENR Energy'also "LENR NRNF non radioactive nuclear flight" for two compilations of worldwide and US developments.

    A Congressional report will be available on Sept. 22, 2016.

    NATIONAL DEFENSE AUTHORIZATION ACT FOR FISCAL YEAR 2017 REPORT OF THE COMMITTEE ON ARMED SERVICES HOUSE OF REPRESENTATIVES ON H.R. 4909 together with ADDITIONAL VIEWS [Including cost estimate of the Congressional Budget Office]https://www.congress.gov/114/crpt/hrpt537/CRPT-114hrpt537.pdf

    Low Energy Nuclear Reactions (LENR) briefing (pg 87)

    Quote

    The committee is aware of recent positive developments in devel- oping low-energy nuclear reactions (LENR), which produce ultra- clean, low-cost renewable energy that have strong national security implications.

    ...the committee directs the Secretary of Defense to provide a briefing on the military utility of recent U.S. industrial base LENR advancements to the House Committee on Armed Services by September 22, 2016 - end quote

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Who

Ugo Bardi is a member of the Club of Rome and the author of "Extracted: how the quest for mineral resources is plundering the Planet" (Chelsea Green 2014)